GM ALTERNATOR SWAP
by Shane Mayall
Yes, there IS a way to get more than 70 amps to power your Brick!
You heard it right! Start with 100 amps, or if you really need more juice, you
can get a whopping 140 amps. Not only that, but if you need to replace it ever,
it's much cheaper than the Volvo replacement (last I checked, the going price
for a 70 amp Volvo alternator, if you don't work at an auto shop, is about $180).
I would be referring to the very popular GM CS-130, which can be found in '87
to '94 GM cars and trucks (except F-bodies: Camaros and the like). I will be
referencing to the '88 Chevrolet Celebrity my mom got rear-ended in and ended
up salvaging. It has a 2.8L MPFI V-6, FWD, auto trans, power-everything and
A/C. Stamped on the case is as follows: 1101832 100A 2113E 12V .meg and the
Delco-Remy tag says: 10463187 321-479 93C.
Now that I'm done clearing all the technical stuff up, here's some information
that'll help the install. PLEASE KEEP IN MIND: this is all done with everything
out of the engine compartment, so your mileage may vary. But I did get what
I believe to be the core measurements for a perfect (at least really damn close)
installation.
- Pulleys ARE interchangeable (fans are NOT)
- You will not use any of the spacers from either pulley (you can't, really)
- You will need a 3/4-inch spacer between the GM body and the GM black arm
thing that is used as some sort of mount on the GM car (I really have no better
way to explain this, you'll understand what I mean when you see it), I used
2 3/8-inch spacers I had sitting around (presumably from something in my stock
Volvo engine compartment)
- The Volvo adjuster fits perfectly on the GM alternator. Thread size is
even exact. You may want to grind a very small amount (about 1/16 inch) of
metal from one side of the "L"-shaped adjuster bar for better clearance between
the GM body
- You will need to grind a small portion of metal from the GM body at one
of the alternator-housing bolts nearest to the adjuster mount (for clearance
for the Volvo adjuster). This small amount of metal you remove will not affect
the alternator at all, but it most likely will void the warranty on any NEW
unit (but you can get a perfectly good junkyard unit, too)
- You will also need to grind a somewhat larger portion of metal (and rubber)
from the Volvo mount (and bushing) at the upper-front rubber bushing mount
(for clearance for the GM alternator fan). This you must do, or it won't turn.
I don't know if this will affect life or alignment or strength of anything
(namely the bushing or the metal mount the bushing goes into), but if you
really want this conversion, there's no way around it (I'm sure there is,
but you'll need to spend money fabricating something, whereas this is free)
- You will also need to grind a minuscule amount of metal from the Volvo
mount at the upper-rear rubber bushing mount. This will aid in more belt slack
when adjusting tension. This small amount will not harm anything
- The last little bit of metal you will need to grind will be from the GM
body at another of the alternator-housing bolts nearest to the front mount.
This, too, will aid in more belt slack when adjusting tension and will not
affect the alternator at all
- Mount the two upper rubber bushings so that the larger portion (I guess
you could call it the flange?) is on the outside of each mount (facing each
other). If you have them any other way, the alternator won't fit, or it will
move out of alignment very easily
Note that most of the grinding is NOT required if you do not want to use the
Volvo adjuster and would rather use a crowbar and brute strength, but WHY??!??!?
The only grinding that is absolutely necessary is the largest amount--the
upper front mount and bushing for clearance for the fan.
Now for the measurements (do with them what you will, I will figure out all spacers,
etc. once I get the engine put in [unless someone wants to add to this with that
info.]):
- Stock GM: Body-to-front edge of pulley: 2 inches
- Stock Volvo: Body-to-front edge of pulley: 2 inches
- GM with Volvo pulley: Body-to-front edge of pulley: 1.75 inches
- Stock Volvo (mounted): Pulley front edge-to-upper power-steering mount
front edge: 2.25 inches
- Stock GM (mounted on Volvo mount): Pulley front edge-to-upper power-steering
mount front edge: 2.5625 inches
- AS INSTALLED (Volvo pulley on GM alternator mounted on Volvo mount): Pulley
front edge-to-upper power-steering mount front edge: 2.5 inches
As you can see, there's really only about a 1/4-inch difference between the two
units (as installed), which I'm almost positive will not affect anything as far
as belt wear, but if you're as much of a perfectionist as I am, you'll do everything
you can to get it to match up exactly, which will only consist of a few washers.
This entire project was done for my '86 744ti, I don't know if it will work as
well or better for the 240 cars, but I know it will at least work, being that
they have the same alternator. For all 940 owners out there, there is nothing
different--the 740s and 940s are the same engine compartment. I have no clue if
this even applies to the V-6. I don't even know if it uses the same alternator
(although I suspect it does, which means it should work).
Now I know I mentioned a 140 amp conversion. If you're like me, you want as much
headroom as possible, and this is as high as I know you can go. JCWhitney and
Summit both sell an "Iceberg" alternator kit for $100 made by Quick Start. It
gives you 140 amp capacity, a monstrous heat-sink, larger rear bearing, installation
stuff and everything else you need to basically have a brand-new, albeit much
more power-handling, alternator. If you go this route, there is NO sense whatsoever
to get a brand-new one from your local auto-parts store, just grab one of the
46,273 units that are sitting around your local junkyard (believe me, there are
so many, you won't have to pull one yourself). BUT! Be sure it has a black arm-thing
(the thing I tried to describe earlier) on the back of the case. I know the Celebrity
(at least the one I had) has this. You need this, otherwise it's not a simple
bolt-on item.
As far as electrical/electronic info goes, I haven't quite worked that out yet,
but if you've done the Ford voltage regulator conversion (which I hope you have
if you've had your brick long enough), then it should be fairly easy to figure
out a simple wiring schematic. My advice: call up or drive down to your local
GM dealer and ask for the terminal designations, volts/resistance/amps of each,
and get a harness/plug while you're there. You may even be able to still use the
Ford regulator, if you know what you're doing (should be fairly easy if you get
all the necessary info from GM). If I don't post anything about this before someone
else gets everything worked out, feel free to add it into this.
This is a near-perfect bolt-on modification. Very very few modifications need
to be done to get it up and running, including the electrical aspect. This should
prove to be substantially more amps than practically all of us need.
Happy motoring!!
Now for the legal:
I have no responsibilities, your mileage may vary, do not use around infants or
suffocation may occur, you don't know me, FDIC insured, any references to any
person living or dead is completely intentional, etc., etc. Copyright yesterday,
before you've read this. |
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